i think i would put it into a hardware wallet most probably
Putting it in a hardware wallet is also risky, since physical hardware can also fluctuate or may be damaged. The best thing to do is create a multiple wallet in different servers and site and also some in physical hardwares. It is best to have a diverse savings than a single item to put your btc into. If you lost one then there are many others that are left.
Ledger Nano HW.1 guarantees a life span of 500.000 cycles which is equal to 30 years of real life time. The cost is really low and its worth it. It works really well and it hasn't any major flaws so far. I insist that anyone who has more than 20 BTC should hold them in a safe hardware wallet like Ledger or Trezor. If the coins were hacked the only one to blame is the person not holding them like they should be holded when in really high amounts.
But you don't really want to store all that in one wallet. Though ulnikely, if something happens, you're left without your coins. Many methods should really be done to keep these coins safe (such as by putting them in multiple wallets and splitting them up).
I'm not sure how it is guarenteed for 500,000 cycles and the coins are still prone to things like theft and other elements such as fire (which is always likely with electrical appliances).